Nobody is suggesting you can have a perfect system. But there's a difference between youthful recklessness and inexperience versus age-related incompetence. The former is difficult to eradicate if not impossible (especially inexperience, everyone is at first). The latter can potentially be quite well tested for.

We've all seen very old people driving very badly, peering inches over the steering wheel etc. and thought fuck off

inb4 something boring about drink driving

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"If the Jewish press still thinks it can intimidate the Labour movement with veiled threats, if they think they can evade our emergency decrees, they should watch out. One day our patience will run out, and the Jews' insolent, lying mouths will be shut for them!"
— Jeremy Corbyn

__________________
"If the Jewish press still thinks it can intimidate the Labour movement with veiled threats, if they think they can evade our emergency decrees, they should watch out. One day our patience will run out, and the Jews' insolent, lying mouths will be shut for them!"
— Jeremy Corbyn